This gallery presents examples of each mammalian family, subfamily or tribe that I've photographed in the wild. With ~155 families of extant mammals, I've photographed just a subset.
[Occasionally I'll include a photo by someone else if we were looking at the same mammal at the same time— see credits].
Missing are families not yet encountered (~55), or those I've seen but not photographed. I haven't tried to see all of the families — missing many small or nocturnal mammals — so this gallery has mostly large diurnal mammals.
    In contrast, I have tried to see all 260 or so bird families, and have a multi-page gallery on birds, limited to one example of each family photographed.

Short-beaked Echidna Tachyglossus aculeatus

Dryandra Woodlands,
W. Australia
(Aug 2008)

Numbat Myrmecobius fasciatus

Dryandra Woodlands, W. Australia
(Aug 2008)

Greater Bilby Macrotis lagotis

Barna Mia, Dryandra Woodlands, W. Australia
(Aug 2008)

Eastern Barred Bandicoot Perameles gunnii

Hobart, Tasmania
(Aug 2008)

Koala Phascolarctos cinereus

Philip I., Victoria, Australia
(Nov 1983)

Western Pygmy Possum Cercartetus concinnus

Cheyne Beach, W. Australia (Aug 2008)

Short-eared Brushtail Possum
Trichosurus caninus

O'Reiily's, Lamington NP, Qld., Australia
(Nov 1983)

Long-nosed Potoroo
Potorous tridactylus

Hobart, Tasmania Australia
(Aug 2008)

Red Kangaroo
Macropus rufus

Waikerie,
South Australia
(Nov 2009)

Whiptail Wallaby
Macropus parryi

Lamington NP, Qld., Australia
(Nov 2016)

Aardvark Orycteropus afer

Brandvlei, South Africa
(July 2005)

photo of Aardvark is © Rita Carratello.
It is a screen shot from her video in the car headlights,
washing out color

Yellow-spotted
Hyrax Heterohyrax brucei

Tarangire NP, Tanzania
(July 2018)

African Elephant
Loxodonta affricanus

Tarangire NP, Tanzania
(July 2018)

American Manatee
Trichechus manatus

Everglades Florida, USA
(Jan 1999)

Yellow
[Six-banded] Armadillo Euphractus sexcinctus

Emas NP, Mato Grosso, Brazil (July 2010)

Brown-throated
Sloth
Bradypus variegatus

Santo Domingo de las Colrados, Ecuador
(Oct 1989)

captive Brown-throated Sloth with Human tourist

Panama Canal, Panama
(Jan 1981)

Hoffmann's Two-toed Sloth
Choloepus hoffmanni

Puerto Viejo, Costa Rica
(Dec 2007)

Giant Anteater Myrmecophaga tridactyla

Emas NP,
Goiás, Brazil
(July 2010)

Southern Tamandua Tamandua tetradactyla

Pantanal, Mato Grosso, Brazil
(July 2010)

Northern Treeshrew Tupaia belangeri

Lung Sin hide
nr Kaeng Krachan NP,
Thailand
(Dec 2012)

Upper left:
Eastern Lesser
Bamboo Lemur
Hapalemur griseus

Berenty Reserve, Madagascar
(Nov 1992)

Lower left:
Ring-tailed Lemur with Human

Right:
Ring-tailed Lemur
Lemur cattus

Berenty Reserve, Madagascar
(Nov 1992)

Weasel Sportive
Lemur Lepilemur mustelinus

Berenty Reserve, Madagascar
(Nov 1992)

Indri
Indri indri

Perinet Reserve, Madagascar
(Nov 1992)

Verreaux's
Sifaka Propithecus verreauxi

Berenty Reserve, Madagascar
(Nov 1992)